Pressure equalization cap and bottle for use therewith

ABSTRACT

The present invention provides a bottle cap for use in association with a bottle. The cap has a roof and sidewall, and is releasably attachable to the bottle. A flexible membrane is attached to the cap whereby an air tight seal between the flexible membrane and the bottle rim is achievable when the cap is attached to bottle. The flexible membrane is moveable responsive to change in pressure inside the bottle and the flexible membrane has an inside between the membrane and the cap. The cap has at least one flow means between the outside of the cap and the inside of the flexible membrane whereby air can move freely between the outside of the cap and the inside of the flexible membrane. The flexible membrane remains attached to the cap when the cap is removed from the bottle.

FIELD OF THE INVENTION

This invention relates to caps for plastic bottles and jars and in particular to caps that equalize pressure in the plastic bottle during cooling. The pressure equalizing cap of the present invention is particularly useful after a plastic bottle or jar has been hot filled or pressurized during filing by artificial means or by air pressure variations due to altitude changes.

BACKGROUND OF THE INVENTION

Plastic bottles are in many instances the preferred bottle for most applications. However, to date products and fluids that are hot filled will more typically be sold in glass bottles, composite cans, metal cans or foil and paper semi-rigid containers. Many bottlers would prefer to use plastic bottles since they are easy to use, easy to manufacture, recyclable, less expensive and generally easier to transport and do not break. But, when plastic bottles are hot filled the plastic bottle will often distort during cooling. In order to reduce this problem, many plastic bottles have panels or stiffeners formed therein. Although these panels help the distortion problem, they pose problems for the bottler since it is more difficult to adhere a label to a bottle with panelling than a smooth surfaced bottle. Generally, distortion of most types of plastic packaging occurs when the plastic container is filled at temperatures above 185⁰ F.

A further drawback of plastic packaging occurs when a plastic-based product package is filled with hot fluid and then capped immediately and left to cool. A partial vacuum forms in the head-space in the container between the upper level of the food and the bottle cap with the consequent pressure differential between the interior of the bottle and the exterior resulting in distortion of the plastic container. This effect is commonly referred to as panelling which is characterized by noticeable and unsightly distortion of the shape of the bottle. In order to balance or eliminate the distortion of the bottle shape created by this partial vacuum it is a common practice to re-engineer the container to have a shape that can naturally counter the distortion induced in the container by cooling. In addition to re-engineering the shape of the container, it is also common practice to add significant gram weight to the container for the purpose of strengthening the walls and therefore resist the contractive forces created by the cooling of the container. Both these solutions add significant cost to the plastic container development costs.

There are a number of prior art devices that are attached to the rim of a bottle and which may be sucked into the bottle when there is a pressure reduction in the bottle. Some examples of these prior art devices are shown in U.S. Pat. No. 756,234 issued to Heath Apr. 5, 1904, U.S. Pat. No. 3,833,142 issued to Owen et al Sep. 3, 1974 and U.S. Pat. No. 4,174,784 issued to Hartung Nov. 20, 1979. The Heath patent is an old patent directed to caps for milk bottles. The cap is a cardboard cap with a central hole formed therein and a thin sheet covers the hole. While a closure such as this provides some advantages when used with a milk bottle it could not be used with a plastic bottle with a threaded closure. The Owen device shows sealing a thin film of a stretchable plastic over the mouth of a plastic container. A breathable liner is placed over the stretchable plastic and then a cap is attached to the bottle. Hartung is similar to Owen in that it includes a membrane that is attached to the mouth of a bottle. Hartung includes a cap that has a vent hole formed in the top thereof. Although these devices show ways of equalizing pressure in a plastic bottle, none of them are attaching the flexible membrane to the cap rather they attached the flexible membrane to the bottle. Accordingly, when the user opens the bottle they will be presented with a bottle opening covered with a flexible membrane that they then have to pierce or remove in some way. Many consumers would find this unappealing. Further, these prior art caps have a vent hole in the cap which poses tamper problems.

There is therefore a need for an economical and efficient means of adapting presently available standard plastic containers as packaging for foodstuffs that must be hot filled. Specifically it would be advantageous to provide a pressure equalization device that is removed when the bottle cap is removed.

SUMMARY OF THE INVENTION

The present invention provides a bottle cap for use in association with a bottle. The cap has a roof and sidewall, and is releasably attachable to the bottle. A flexible membrane is attached to the cap whereby an air tight seal between the flexible membrane and the bottle rim is achievable when the cap is attached to the bottle. The flexible membrane is moveable responsive to change in pressure inside the bottle and the flexible membrane has an inside between the membrane and the cap. The cap has at least one flow means between the outside of the cap and the inside of the flexible membrane whereby air can move freely between the outside of the cap and the inside of the flexible membrane.

In another aspect, the invention provides a bottle and cap assembly which comprises a pressure equalizing cap and a bottle having a generally smooth portion and a neck portion. The generally smooth cylindrical portion is free of panelling sections and the generally smooth portion is designed to have a label adhered thereto.

Further features of the invention will be described or will become apparent in the course of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a blown apart perspective view of the cap of the present invention in association with a bottle;

FIG. 1 a is a perspective view similar to that shown in FIG. 1 but showing the cap assembled and removed from the bottle;

FIG. 2 is a cross sectional view of the cap of the present invention screwed onto a bottle;

FIG. 3 is a blown apart perspective view of an alternate cap constructed in accordance with the present invention;

FIG. 4 is a cross sectional blown apart view of the cap of FIG. 3;

FIG. 5 is a cross sectional view of the cap of FIG. 3 screwed onto a bottle;

FIG. 6 is a cross section view of another alternate cap constructed in accordance with the present invention, wherein the cap has an upper cavity;

FIG. 7 is a cross sectional blown apart view of the cap of FIG. 6 screwed onto a bottle;

FIG. 8 is a cross sectional view of the further alternate cap constructed in accordance with the present invention, wherein the cap has an inner portion, an outer portion and an upper cavity; and

FIG. 9 is a blown apart perspective view of another alternate cap constructed in accordance with the present invention similar to that shown in FIG. 3 and further including an outer sealing ring;

FIG. 10 is a blown apart cross sectional view of the embodiment shown in FIG. 9;

FIG. 11 is a blown apart perspective view of another alternate cap constructed in accordance with the present invention including multiple bubbles;

FIG. 12 is a cross sectional view of the cap of FIG. 11;

FIG. 13 is a cross section view of another alternate view of a cap constructed in accordance with the present invention similar to that shown in FIGS. 11 and 12 but showing more bubbles;

FIG. 14 is a cross sectional view of another alternate view of a cap constructed in accordance with the present invention similar to that shown in FIGS. 11 and 12 but with an upper cavity; and

FIG. 15 is a cross sectional view of another alternate view of a cap constructed in accordance with the present invention similar to that shown in FIG. 14 but with an upper cavity.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, the present invention is directed to a cap 10 that is adapted to be attached to a bottle 12. The cap 10 of the present invention allows for pressure equalization as the bottle 12 cools.

Preferably cap 10 includes an outer cap 14, an inner cap 16 and a membrane 18. The inner cap 16 is nested in the outer cap 14. A flexible membrane 18 is positioned in the inner cap 16. Inner cap 16 has an aperture 20 formed therein. There is an air space 22 between outer cap 14 and inner cap 16. The flexible membrane 18 is moveable responsive to changes in pressure. Preferably, the flexible membrane 18 is made from food grade plastic. The flexible membrane 18 is preformed in a bubble shape. When the pressure is equal on both sides of the flexible membrane 18; it is flaccid. Alternatively it there is a differential in pressure between one side of the flexible membrane 18 then it will be pulled toward the bubble shape. The flexible membrane is made of material that has gas barrier characteristics. For example the flexible membrane may be made of EVOH (ethyl vinyl alcohol), PVA (polyvinyl alcohol), PVDC (polyvinyl dichloride), or some other chemistry to make the membrane more impervious to gas ingress Preferably the flexible membrane 18 has an outer rim 19 that is attached to the inside of the inner cap 16. A sealing ring 21 may be used to seal the flexible membrane 18 to the inner cap 16. It will be appreciated by those skilled in the art that there may be alternate ways of adhering the flexible membrane 18 to the inner cap 16.

The bottle 12 has a generally smooth portion 24. Preferably the bottle is cylindrical but if desired it could also be generally square in cross section. The generally smooth portion makes it easy for the bottlers to adhere a label 26 thereto. The generally smooth portion 24 extends upwardly into a neck 28. Preferably the bottle 12 includes a bottle threaded closure 30. Similarly the cap 10 includes a cap threaded closure 32 formed on the inside of the inner cap 16 and which is adapted to engage the bottle threaded closure 30. The flexible membrane 18 has an inside 21 between the membrane and the cap.

The cap 10 and bottle 12 of the present invention are particularly useful in the hot fill of plastic bottles. The cap 10 of the present invention allows the pressure to equalize in the bottle 12 as the product therein cools. By providing a cap 10 that allows for the equalization of pressure in the bottle during cooling it reduces and in some cases eliminates the need for engineered panels on the bottle. Thus the cap of the present invention allows for the use of a bottle with a generally smooth portion 24. This generally smooth portion makes it considerably easier to adhere a label 26 to the bottle than bottles that have engineered panels on the sides thereof. Current bottles that are hot filled are typically made of heat set PET which requires engineered panels and a substantial increase in the gram weight of the container. It will be appreciated by those skilled in the art that if the engineered panels are not required the gram weight of the bottle can be reduced by approximately 25%. Accordingly, the bottle of the present invention provides both a cost saving and an environmental saving.

In use the bottle 12 is filled and then the cap 10 is attached to the bottle 12. The cap 10 is attached such that there is initially an air-tight seal between the membrane 18 and the rim 34 of the bottle 12. The flexible membrane 18 is initially in a flaccid state as shown at 23 in phantom in FIG. 2. As the heated product cools a vacuum is created inside the bottle and the flexible membrane 18 is sucked into the bottle. It will be appreciated by those skilled in the art that it is only when the cap is first attached to the bottle that it is important to achieve an air-tight seal between the flexible membrane 18 and the rim of the bottle. Thereafter once the cap has been opened the quality of the seal is less important.

Once the cap is removed from the bottle since the flexible membrane 18 is attached to the cap it is removed with the cap as shown in FIG. 1 a, It will be appreciated by those skilled in the art that this is a clear advantage over the prior art that has a seal attached to the rim of the bottle. Such a prior art seal can often be very difficult to remove. As well, these prior art seals are relatively unsightly and by moving the seal into the cap this consumer unfriendly appearance is reduced. Since the flexible membrane is attached to the cap rather than the bottle it is further distanced from the contents of the bottle thereby reducing the likelihood of the membrane coming in direct contact with the contents.

Referring to FIGS. 3, 4 and 5, an alternate cap constructed in accordance with the present invention is shown generally at 40. Cap 40 has a plurality of grooves 42 that extend through the threaded closure 44 and along the roof of the cap 40. The cap 40 also includes a flexible membrane 46 and a sealing ring 48. The sealing ring 48 helps to secure the flexible membrane 46 to the cap 40. As can best be seen in FIG. 5, the grooves 42 are arranged such that when the cap is secured on the bottle 12 the grooves 42 provide a means for air to enter the inside 50 of flexible membrane. Thus as described above when a bottle is filled with hot product and the product cools the flexible membrane can be sucked into the bottle 12 and air is then sucking into the inside 50 of the membrane 46. As described above when the bottle 12 is initially sealed there is an airtight seal between the flexible membrane 46 and rim 34 of the bottle 12 through the sealing ring 48.

Another alternate embodiment is shown in FIGS. 6 and 7. Cap 60 is similar to that shown in FIGS. 3, 4 and 5 but having a cap upper extension 62. This upper extension is particularly useful in the event that the bottles are filled at a higher altitude and as the bottle is brought to a lower altitude the flexible membrane 46 will tend to be sucked into the upper extension 62. The remainder of the cap 60 is as described with regard to cap 40. Specifically there are a plurality of grooves 42 that extend through threaded closure 44. The flexible member 46 is held in place with a sealing ring 48. It will be appreciated by those skilled in the art that the flexible membrane 46 may be sucked into the bottle 12 or sucked into the upper extension 62 as the pressure in the bottle 12 changes.

Another alternate embodiment is shown in FIG. 8. Essentially cap 70 is a mixture of the features of cap 10 and cap 60. Specifically cap 70 has an inner cap 72 nested inside of outer cap 74. Outer cap 74 has an upper extension 76. Inner cap has a central opening 78 so that flexible membrane 18 can be sucked into the upper extension 76. As described above inner cap 72 and outer cap 74 allow air to flow therebetween such that air can be sucked into the inside 21 of the membrane 18.

Referring to FIGS. 9 and 10, an alternate cap is shown generally at 80. Cap 80 is similar to cap 40 shown in FIGS. 3 and 4. In cap 80 sealing ring 82 is an inner sealing ring and cap 80 further includes an outer sealing ring 84. The remainder of cap 80 is as shown in FIGS. 3 and 4 with regard to cap 40. Outer sealing ring 84 helps to stiffen the flexible membrane 46 during manufacture and use.

Referring to FIGS. 11 and 12, an alternate embodiment of the cap of the present invention is shown generally at 90. Cap 90 is similar to the caps shown previously but the flexible membrane 92 is preformed into a plurality of bubbles 94. A sealing disc 96 has a plurality of apertures 98 formed therein. When assembled each aperture 98 is in registration with a bubble 94. A plurality of grooves 100 are arranged such that each extends through the centre of the cap 90. Flexible membrane 92, sealing disc 96 and cap 90 are arranged such that when assembled each bubble 94 is in registration with an aperture 98 and at least one groove 100. An alternative to cap 90 is shown in FIG. 13 at 102 wherein cap 102 includes a plurality of bubbles 104. Bubbles 104 are smaller than bubbles 94 such that for the same diameter of caps there will be more bubbles 104 than bubbles 94. Caps 106, 108 shown in FIGS. 14 and 15 are similar to those shown in FIGS. 12 and 13 respectively but further including an upper cavity 110, 112. In all other aspects caps 106 and 108 are the same as cap 90 and 102.

Caps having a membrane with a plurality of bubbles are particularly adapted for use with wide mouth jars. If a single bubble was used with a wide mouth jar there would be a risk that the bubble could be seen below the cap by a consumer which would be undesirable. As well, there is the risk that the bubble might be sucked into the food product which also would be undesirable.

As used herein, the terms “comprises” and “comprising” are to construed as being inclusive and opened rather than exclusive. Specifically, when used in this specification including the claims, the terms “comprises” and “comprising” and variations thereof mean that the specified features, steps or components are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

It will be appreciated that the above description related to the invention by way of example only. Many variations on the invention will be obvious to those skilled in the art and such obvious variations are within the scope of the invention as described herein whether or not expressly described. 

1. A bottle cap for use in association with a bottle having a bottle rim comprising: a cap having a roof and sidewall, the cap being releasably attachable to the bottle; a flexible membrane attached to the cap whereby an air tight seal between the flexible membrane and the bottle rim is achievable when the cap is attached to the bottle, the flexible membrane being moveable responsive to change in pressure inside the bottle and the flexible membrane having an inside between the membrane and the cap; at least one flow means between the outside of the cap and the inside of the flexible membrane whereby air can move freely between the outside of the cap and the inside of the flexible membrane.
 2. A bottle cap as claimed in claim 1 wherein the flexible membrane has at least one bubble preformed therein and wherein each bubble is flaccid when the pressure on either side of the flexible membrane is generally equal.
 3. A bottle cap as claimed in claim 2 wherein the cap has a threaded closure formed along the sides thereof adapted to engage a threaded closure on the bottle.
 4. A bottle cap as claimed in claim 3 wherein the cap has at least one groove extending from the roof down the side, through the threaded closure and wherein the groove is the flow means.
 5. A bottle cap as claimed in claim 4 further including a plurality of grooves.
 6. A bottle cap as claimed in claim 5 further including a sealing ring that is attached between the flexible membrane and the cap.
 7. A bottle cap as claimed in claim 6 wherein the sealing ring is an inner sealing ring is an inner sealing ring and further including an outer sealing ring.
 8. A bottle cap as claimed in claim 5 wherein the cap has a rim and further including an upper extension that extends upwardly from the rim and whereby the flexible membrane may extend upwardly into the cap upper extension.
 9. A bottle cap as claimed in claim 8 further including a sealing ring that is attached to the flexible membrane.
 10. A bottle cap as claimed in claim 9 wherein the sealing ring is an inner sealing ring is an inner sealing ring and further including an outer sealing ring.
 11. A bottle cap as claimed in claim 3 wherein the cap has a rim and further including an upper extension that extends upwardly from the rim and whereby the flexible membrane may extend upwardly into the cap upper extension.
 12. A bottle cap as claimed in claim 11 further including a sealing ring that is attached between the flexible membrane and the cap.
 13. A bottle cap as claimed in claim 12 wherein the sealing ring is an inner sealing ring is an inner sealing ring and further including an outer sealing ring.
 14. A bottle cap as claimed in claim 2 wherein the cap includes an outer cap portion, an inner cap portion, and a means of keeping the outer cap portion and the inner cap portion nested together, the inner cap portion loosely fits within the outer cap portion such that air can flow therebetween, the inner cap portion has an aperture formed therein thereby allowing air between the inside of the flexible membrane and the outside of the cap.
 15. A bottle cap as claimed in claim 14 wherein the inner cap portion has a threaded closure formed along the sides thereof adapted to engage a threaded closure on the bottle.
 16. A bottle cap as claimed in claim 15 wherein the outer cap portion has a lower edge and further including a lip extending inwardly around the lower edge of the outer cap portion and the lip acts as a stop to keep the inner cap portion and the outer cap portion nested together.
 17. A bottle cap as claimed in claim 16 further including a sealing ring that is attached between the flexible membrane and the cap.
 18. A bottle cap as claimed in claim 17 wherein the sealing ring is an inner sealing ring is an inner sealing ring and further including an outer sealing ring.
 19. A bottle cap as claimed in claim 16 wherein the outer cap portion has a rim, the aperture in the inner cap portion is a central opening and further including an upper extension that extends upwardly from the rim and whereby the flexible membrane may extend upwardly through the central opening in the inner cap portion and into the outer cap portion upper extension.
 20. A bottle cap as claimed in claim 2 further including a plurality of bubbles.
 21. A bottle cap as claimed in claim 1 wherein the flexible membrane includes a gas barrier.
 22. A bottle cap as claimed in claim 21 wherein the flexible membrane is made from one of ethyl vinyl alcohol, polyvinyl alcohol, and polyvinyl dichloride.
 23. A bottle and cap assembly comprising: a pressure equalizing cap; and a bottle having a generally smooth portion and a neck portion, the generally smooth portion being free of engineered panels and wherein the generally smooth portion is designed to have a label adhered thereto.
 24. A bottle and cap assembly as claimed in claim 23 wherein the generally smooth portion is cylindrical.
 25. A bottle and cap assembly as claimed in claim 24 wherein the bottle has a rim and the pressure equalizing cap includes a cap having a roof and sidewall, the cap being releasably attachable to the bottle; a flexible membrane attached to the cap whereby an air tight seal between the flexible membrane and the bottle rim is achievable when the cap is attached to the bottle, the flexible membrane is moveable responsive to change in pressure inside the bottle, and the flexible membrane has an inside between the membrane and the cap; and at least one flow means between the outside of the cap and the inside of the flexible membrane whereby air can move freely between the outside of the cap and the inside of the flexible membrane.
 26. A bottle cap and assembly as claimed in claim 25 wherein the flexible membrane has at least one bubble preformed therein and wherein each bubble is flaccid when the pressure on either side of the flexible membrane is generally equal.
 27. A bottle cap and assembly as claimed in claim 26 wherein the cap has a plurality of threads formed along the sides thereof adapted to engage a plurality of threads on the bottle.
 28. A bottle cap and assembly as claimed in claim 27 wherein the cap has at least one groove extending from the roof down the side, through the plurality of threads and wherein the groove is the flow means.
 29. A bottle cap and assembly as claimed in claim 28 further including a plurality of grooves.
 30. A bottle cap and assembly as claimed in claim 29 further including a sealing ring that is attached to the flexible membrane.
 31. A bottle cap and assembly as claimed in claim 30 wherein the cap has a rim and further including an upper extension that extends upwardly from the rim and whereby the flexible membrane may extend upwardly into the cap upper extension.
 32. A bottle cap and assembly as claimed in claim 25 wherein the cap has a rim and further including an upper extension that extends upwardly from the rim and whereby the flexible membrane may extend upwardly into the cap upper extension.
 33. A bottle cap and assembly as claimed in claim 26 wherein the cap includes an outer cap portion, an inner cap portion, and a means of keeping the outer cap portion and the inner cap portion nested together, the inner cap portion loosely fits within the outer cap portion such that air can flow therebetween, the inner cap portion has an aperture formed therein thereby allowing air between the inside of the flexible membrane and the outside of the cap.
 34. A bottle cap and assembly as claimed in claim 33 wherein the inner cap portion has a plurality of threads formed along the sides thereof adapted to engage a plurality of threads on the bottle.
 35. A bottle cap and assembly as claimed in claim 34 wherein the outer cap portion has a lower edge and further including a lip extending inwardly around the lower edge of the outer cap portion and the lip acts as a stop to keep the inner cap portion and the outer cap portion nested together.
 36. A bottle cap and assembly as claimed in claim 35 wherein the outer cap portion has a rim, the aperture in the inner cap portion is a central opening and further including an upper extension that extends upwardly from the rim and whereby the flexible membrane may extend upwardly through the central opening in the inner cap portion and into the outer cap portion upper extension.
 37. A bottle cap and assembly as claimed in claim 26 further including a plurality of bubbles.
 38. A bottle cap and assembly as claimed in claim 25 wherein the flexible membrane remains in the cap when the cap is removed from the bottle.
 39. A bottle cap and assembly as claimed in claim 25 wherein the flexible membrane includes a gas barrier.
 40. A bottle cap and assembly as claimed in claim 39 wherein the flexible membrane is made from one of ethyl vinyl alcohol, polyvinyl alcohol, and polyvinyl dichloride. 